However,
when Columbia reached orbit, it was 11 kilometers (7 miles)
short of its target. This was due to premature main engine
cutoff an instant before the scheduled cutoff. This problem
was traced to a hydrogen leak in the No. 3 main engine nozzle.
The leak was caused when a liquid oxygen post pin came out
of the main injector during main engine ignition, striking
the hotwall of the nozzle and rupturing three liquid hydrogen
coolant tubes. Columbia eventually reached its proper altitude
and continued its mission.

On Flight
Day 1, the shuttle crew successfully deployed Chandra. The
observatory was propelled into orbit by a two-stage Inertial
Upper Stage, or IUS. Following
the second IUS burn, Chandra's solar arrays were deployed
and the IUS separated from the observatory as planned.

During
the rest of the mission the crew activated secondary payloads
and experiments, including the Southwest Ultraviolet Imaging
System which was used to capture ultraviolet imagery of Earth,
the Moon, Mercury, Venus and Jupiter.

The astronauts
monitored several plant growth experiments and collected data
from a biological cell culture experiment. They used the exercise
treadmill and the Treadmill Vibration Information System to
measure vibrations and changes in microgravity levels caused
by on-orbit workouts. High-Definition Television equipment
was tested for future use on both the shuttle and the International
Space Station to conform to evolving broadcasting industry
standards for television products.

STS-93
Commander Eileen Collins, the first woman to command a
shuttle crew, floats on Columbia's middeck during a free
moment.

Collins
Becomes First Female Shuttle Commander
With the launch of STS-93 on July 22, 1999, Col. Eileen
Collins became the first woman to command a space shuttle
mission.

Collins
became an astronaut in July 1991. Her first space flight was
in February 1995 as pilot of STS-63.
Her participation in this mission to rendezvous Space Shuttle
Discovery with the Russian Space Station Mir made her the
first woman to pilot a space shuttle. She also served as pilot
on STS-84
in May 1997. This shuttle mission was the sixth to dock with
Mir. Collins and her fellow crewmembers conducted several
experiments and transferred nearly 3.6 metric tons (4 tons)
of supplies and experiment equipment between Space Shuttle
Atlantis and the Russian space station.